The function of the Animal Core is to produce and maintain all of the animals required for the scientific projects for this and several other program project grants. The specific services of the Animal Core personnel include: 1) Production of transgenic and knockout mice, 2) Production of large volumes of scrapie-infected hamster brains for purification, 3) Performing experimental inoculations, neurologic scoring of animals, data collection, and tissue collection, 4) Providing transportation of animals and tissues between the laboratory and the animal facility; 5) Production of antibodies in mice and rabbits for experimental use, 6) Providing all animal care and veterinary care. The Animal Core operates in two purpose-build facilities in the Hunter's Point area of San Francisco, approximately 12 miles from the main UCSF campus. Its activities are directed by Dr. Prusiner and Dr. Marilyn Torchia, a laboratory animal veterinarian. Building 830B is a new nine room transgenic mouse breeding facility which houses or large breeding colony. Building 830 houses all the experimental animals in 21 rooms, under BSL 2 and 3 biocontainment.